1. Field of the Invention
This invention generally relates to grasping devices, and more particularly to a mechanical apparatus for selectively grasping and moving individual heated articles at remote locations.
2. Description of the Prior Art
As is well known, flat glass is produced in a continuous tank-type melting furnace wherein raw batch materials are continuously delivered to the charging end of the furnace, melted and refined as they move through the furnace, and then withdrawn from its delivery end as a continuous ribbon. In furnaces of this type, flames for melting the raw batch material are introduced through a series of spaced ports arranged along each of the opposed longitudinal side walls, the ports leading to sources of supply of fuel and preheated combustion air. The combustion air is preheated by passing through the checkerwork of the regenerators associated with the ports being fired and through which the hot waste gases have previously passed. Two two series of ports are alternately operated so that first one series of ports is fired with the opposite series exhausting the hot waste gases. Then at periodic intervals of about 20 to 30 minutes, the operating condition of the two series of ports is reversed; that is, the ports being fired serve as the exhaust ports and the ports through which the hot waste gases were being exhausted serve as the firing ports. Also, it should be noted that the operating temperatures in the port areas of the furnace are in the neighborhood of 2700.degree. F. (1500.degree. C.). Thus, it is apparent that the regenerators are subjected to severe use over extended periods of time as the average campaign of a furnace, that is, the period of continuous operation, may be five years or more. The severe conditions under which the regenerators operate cause extensive wear and corrosion of their checkerwork structures necessitating frequent repairs which, of course, are most difficult to perform because of the extremely high temperatures in the regenerator areas of the furnace.